Study of Synchrotron Radiation Near-Edge X-Ray Absorption Fine-Structure of Amorphous Hydrogenated Carbon Films at Various Thicknesses

The compositions and bonding states of the amorphous hydrogenated carbon films at various thicknesses were evaluated via near-edge X-ray absorption fine-structure (NEXAFS) and elastic recoil detection analysis combined with Rutherford backscattering spectrometry. The absolute carbonsp2contents were determined to decrease to 65% from 73%, while the hydrogen contents increase from 26 to 33 at.% as the film thickness increases. In addition, as the film thickness increases, theπ⁎(C=C),σ⁎(C–H),σ⁎(C=C), andσ⁎(C≡C) bonding states were found to increase, whereas theπ⁎(C≡C) andσ⁎(C–C) bonding states were observed to decrease in the NEXAFS spectra. Consequently, the film thickness is a key factor to evaluate the composition and bonding state of the films.